The present invention relates to a flight control surface control unit for controlling the swinging angle of a flight control surface by swinging the flight control surface of an aircraft.
Generally, a flight control surface 11 (elevator, rudder, etc.) of an aircraft is swingably supported on an airframe 12 of the aircraft with a pin 13 as shown in FIGS. 5 and 6. Such a flight control surface 11 is swung only by a required angle under the direct control of a pilot during the flight.
In the related art, a hydraulic servo cylinder 14 of a linear drive system, which is reliable and has large output per unit volume, has been used as a control unit for controlling the swinging angle of such a flight control surface 11. A plurality of such cylinders 14, two in this case, are installed in side-by-side arrangement, each head side of the cylinder 14 is rotatably connected to the airframe 12 (main wing, tail wing, etc.) via a pin 15, and the distal end of piston rod 16 thereof is rotatably connected to the distal end of a fixed link 17 projecting from the vicinity of the pivot of the flight control surface 11 via a pin 18.
The linear movement of the piston rod 16 of the cylinder 14 is converted into the rotational movement by means of the fixed link 17, whereby the flight control surface 11 is swung about the pin 13 (pivot). The reference numeral 19 designates a fairing for covering the flight control surface 11, the fixed link 17 projected from the airframe 12, and the cylinder 14, and the fairing 19 includes an airframe side fearing 19a fixed on the airframe 12 and a wing-side fearing 19b fixed on the flight control surface side 11.
However, in such a flight control surface control unit in the related art, since there exists a portion projecting from the flight control surface 11 and the airframe 12 (fixed link 17, cylinder 14), the fairing 19 for covering these portions is required. However, there arises such aproblem that the fairing 19 has high air resistance during the flight, especially, that the air resistance thereof drastically increases in association with recent speeding up of the aircraft, and thus the fuel consumption efficiency drops to a large extent.
Accordingly, it is an object of the invention to provide a flight control surface control unit that allows improvement of the fuel consumption efficiency by reducing air resistance during the flight.
The object of the invention may be achieved by providing a flight control surface control unit for controlling a swinging angle of a flight control surface of an aircraft by providing a swinging force to the flight control surface and swinging the flight control surface about a pivot. The unit includes an actuator mounted on an airframe of the aircraft with a final output shaft of the actuator positioned coaxially with the pivot of the flight control surface. Further, the final output shaft of the actuator and the flight control surface are connected. The actuator is preferably an oscillating rotary actuator.
Since the final output shaft swings the flight control surface by the use of the actuator (the oscillating rotary actuator) that is coaxial with the pivot of the flight control surface according to the invention, a conversion mechanism (such as a fixed link) for converting the linear movement into the rotational movement as in the related art is not necessary anymore, and thus the fairing for covering the conversion mechanism is not necessary. This allows reduction of air resistance of the aircraft during the flight and thus improvement of the fuel consumption efficiency.
According to the invention as recited in claim 2, the mounting space on the airframe side maybe reduced, which allows achievement of weight reduction and downsizing of the aircraft.
In the case where a plurality of (oscillating rotar) actuators including a drive motor and a gear reducer are provided, and the gears of the gear reducer in any one of (oscillating rotary) actuator are jammed (seized, fixed or the like), rotation of the final output shaft of the jammed (oscillating rotary) actuator is constrained, and thus swinging movement of the flight control surface to be made by the normal (oscillating rotary) actuator is impaired. Therefore, according to the invention as recited in claim 3, a clutch is provided for disconnecting the final output shaft of the (oscillating rotary) actuator from the fixed side when the (oscillating rotary) actuator is jammed and practically freeing rotation thereof. This allows other normal (oscillating rotary) actuators to swing the flight control surface and to continue controlling.
According to the invention as recited in claim 4, jamming between gears, that is, the failure, can be detected easily, and when the failure is corrected, control of the flight control surface may be continued as is.
According to the invention as recited in claim 5, since the connecting point of the clutch, that is, the position of fixed claws and revolving claws, may be stood significantly away from the center of rotation, the connecting force of the clutch may be increased.
According to the invention as recited in claim 6, fluttering of the flight control surface that may occur when all the pluralities of oscillating rotary actuators are broken down may be prevented.
The present disclosure relates to the subject matter contained in Japanese patent application No. P2001-311003 (filed on Oct. 9, 2001), which is expressly incorporated herein by reference in its entirety.